Bone fractures are typically treated by restoring the fractured pieces of bone to their natural positions and maintaining those positions while the bone heals. Briefly, the fractured bone(s) is aligned in good position (also called reduction) and then immobilized with a cast that holds the bones in position and immobilizes the joints above and below the fracture. When the initial post-fracture edema or swelling goes down, the fracture may be placed in a removable brace or orthosis. In cases of complex or open fractures, surgical nails, screws, plates and wires may be used to internally hold the fractured bone together. The surgical implantation of these internal fixation devices, however, may cause extensive trauma to the patient, increase potential for infection, and require second surgery for their removal. An alternative to internal fixation devices is the external fixation device. Pins or screws are placed into the broken bone above and below the fracture site to reposition and immobilize the bone fragments. The pins or screws are connected to a metal bar or bars outside the skin to form a stabilizing frame that holds the bones in the proper position so they can heal. After an appropriate period of time, the external fixation device is removed.
Distal radius fracture is a common fracture found in many slip-and-fall cases. Since distal radius fractures have a tendency to collapse, maintenance of fracture reduction is of great significance. Although many external fixation devices have been developed for the treatment of bone fractures, for example in U.S. Pat. No. 1,789,060, U.S. Pat. No. 2,333,033, U.S. Pat. No. 2,435,850, U.S. Pat. No. 4,135,505, U.S. Pat. No. 4,271,832, U.S. Pat. No. 4,299,202, U.S. Pat. No. 4,488,542, U.S. Pat. No. 4,922,896, U.S. Pat. No. 5,728,096 and U.S. Pat. No. 5,951,556, these devices are generally cumbersome and expensive, and are difficult to be readily employed in a restricted spatial area, such as the wrist. There still exists a need for lightweight, non-bridging external fixation devices that allows for direct fixation of a distal radius fracture, maintenance of the radiological parameters, and early mobilization of the wrist.